During the Jurassic Period, Europe was covered by a shallow sea in which a rich fauna was encapsulated in sequences of limestones and shales. These Jurassic rocks were the training ground for many of the early geologists as they began to formulate some of the basic precepts of geology. Foremost amongst these was William Smith (1769-1839) who was the first to discover how to use fossils to correlate between separated outcrops. He gained his knowledge and understanding of fossils in his profession of a surveyor and in the building of canals throughout southern England where the canals were cut into these highly fossiliferous Jurassic rocks. At first, Smith simply collected fossils he found in his daily pursuits because they were interesting curios. At the time, assembling collections of fossils was a common hobby. Most of the individuals, including Smith, who made such collections had no idea of their geologic significance. That was to change one day in 1 798 when he made the discovery that anywhere it was encountered, every individual rock formation contained a diagnostic suite of fossils even though the lithology may have changed slightly. It then occurred to him that the individual formations could be identified simply by collecting and identifying the fossils they contained. This idea was reinforced when he visited a friend, also an avid fossil collector, who was able to tell Smith the exact formation from which each of his fossils had been collected. It was then and there that the use of fossils for correlation and identification of rock formations and the subsequent geologic specialty of stratigraphy was born. For his work, Smith was not only given the unofficial title of the Father of English Geology but also the nickname of ."Strata" as in William "Strata" Smith.
Renton, John J. and Repine, Thomas, "The Jurassic Period" (2016). Readings and Notes. 19.